Prevention of foaming of oils



United States Patent 3,066,100 PREVENTION OF FOAMING 0F OILS Charles E. Trautman, Cheswick, Pa., assiguor to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware No Drawing. Filed Dec. 7, 1959, Ser. No. 857,551 Claims. (Cl. 25249.6)

This invention relates to the prevention of foaming of oils and oil compositions, particularly mineral and synthetic lubricating oils and lubricants containing them. By the term synthetic lubricating oil I mean a compound or composition of non-mineral origin having a majority of the lubricating properties of a mineral oil of lubricating grade.

Oils and oil compositions, including both mineral oils and synthetic oils of lubricating grade tend to foam or froth when agitated in the presence of gases or vapors, such as air, steam, oil vapors, products of combustion and the like. The amount of foam or froth varies with the conditions under which the oil composition is agitated as well as the character of the composition. Under some conditions, the volume of foam or froth produced is many times that of the original oil, and even with mild agitation, substantial amounts of foam are produced in many oil compositions. In preparing and using such oils and oil compositions commercially, they are subjected to agitation under a wide range of conditions and frequently undesirable amounts of foam or froth are produced.

Various means of combating such foaming of oils and oil compositions have been proposed. For instance, mechanical devices have been proposed for destroying or breaking foam as it is formed. Likewise, the incorporation of certain oil-soluble compounds in the oil has been proposed as a means for preventing foaming. Unfortunately, no compound of this type has been found which is completely satisfactory in all types of oils. While some compounds have effectively reduced foaming in a mineral oil, they have been less effective or completely ineffective in a synthetic oil. Some of the prior anti-foam agents which have effectively inhibited the foaming of a mineral oil have actually increased the amount of foam formed in a synthetic oil. In some instances, the prior anti-foam agents have reduced foaming of synthetic oils for a short period of time, their effectiveness rapidly diminishing in use. In other instances the prior anti-foam agents have been added to the oil in such amounts that the desirable lubricating properties of the oil are impaired.

Among the objects achieved by this invention is the provision of an improved method of preventing foaming of oils and oil compositions, particularly mineral and synthetic lubricating oils, in which the normal foaming tendency of the oil is effectively abated or suppressed for long periods of use without deleteriously affecting the other properties of the oil.

Another object achieved by this invention is the provision of new and improved anti-foam compositions capable of abating and inhibiting foaming of mineral and synthetic oils and oil compositions when dispersed therein in minute amounts.

A furtherobject achieved by the present invention is the provision of-new and improved oil compositions, particularly improved mineral and synthetic lubricating oils and lubricants, having marked resistance to foaming and other advantageous properties, including resistance to 3,066,100 Patented Nov. 27, 1962 "ice emulsification and containing minute amounts of an oilinsoluble anti-foam composition finely dispersed therein.

I have discovered that foaming of oils, both mineral and synthetic oils, can be effectively suppressed or prevented without substantial modification of the desirable properties of such oils by forming in the oil a stable, fine dispersion of a small amount of an anti-foam composition consisting essentially of a substantially oil-insoluble liquid polyhydric alcohol and a trialkyl[(perfluoroheptyDamidopropylJammonium halide. I have found that a synthetic oil as well as a mineral oil containing such an antifoam composition as a stable, finely dispersed phase is markedly resistant to foaming. The presence of the finely dispersed insoluble liquid phase in the oil apparently causes the film of the oil foam to rupture, thereby quickly destroying the foam. In fact, particularly when an adequate amount of anti-foam composition is used, its presence so rapidly breaks the oil foam that substantiall all foam is destroyed as fast as it is formed.

The polyhydric alcohol contemplated for use according to this invention is selected from the class consisting of dihydric and trihydric alcohols. Typical alcohols within this class include, for example, the glycols, such as ethylene glycol, propylene glycol, trimethylene glycol, dimethylethylene glycol and the like and glycerol. These alcohols are particularly advantageous for the present purposes because of their insolubility or extremely low solubility in synthetic oils.

The trialkyl[ (perfluoroheptyl) amidopropyl] ammonium halide contemplated for use according to this invention is one wherein one of said alkyl radicals contains from 8 to 12 carbon atoms and each of the other two said alkyl radicals contains from 1 to 4 carbon atoms. Exemplary of such componds are:

Diilnehtldiyloctyu (perfluoroheptyl) amidopropyl] ammonium a es; -Diethyloctyl[ (perfluoroheptyl) amidopropyl] ammonium halides; Diplrtilrayloctyl (perfluoroheptyl) amidopropyl] ammonium a es; Dibutyloctyl[ (perfluoroheptyl) amidopropyl] ammonium halides;

' Mouomethylmonoethyloctyl[ (perfluoroheptyl) amidopropyl] ammonium halides;

Mouomethylmonobutyloctyl (perfluoroheptyl) amidopropyl] ammonium halides;

Monoethylmonobutyloctyl[ (perfluoroheptyl) amidopropyl] ammonium halides;

Dimethylnonyl (perfluoroheptyl) amidopropyl] ammonium halides;

Diethyluonyl[ (perfluoroheptyl) amidopropyl] ammonium halides;

Dipropylnonyl perfluoroheptyl) amidopropyl] ammonium halides;

Dibutylnouyl (perfluoroheptyl) amidopropyl] ammonium halides;

Dimethyldecyl (perfluoroheptyl) amidopropyl] ammonium halides;

Diethyldecyl[ (perfluoroheptyl) amidopropyl] ammonium halides;

Dipropyldecyl perfluoroheptyl) amidopropyl] ammonium halides;

Dibutyldecyl[ (perfluoroheptyl) amidopropyl] ammonium halides;

Dimethylundecyl[ (perfluoroheptyl) amidopropyl] ammonium halides;

Diethylundecyl[ (perfluoroheptyl) amidopropyl] ammonium halides;

Dipropylundecyl[ (perfluorohep tyl) amidopropyl] ammonium halides;

Dibutylundecyl[ (perfluoroheptyl) amidopropyl] ammonium halides;

Dimethyldodecyl] (perfluoroheptyl)amidopropyl]-ammonium halides;

Diethyldodecyl[ (p erfluoroheptyl) amidopropyl] ammonium halides;

Dipropyldodecyl (perfluoroheptyl amidopropyl] ammonium halides; and

Dibutyldodecyl[ (perfluoroheptyl) amidopropyl] ammonium halides;

A preferred class of compounds which can be used in accordance with the invention are dimethyloctyl-, dimethylnonyl-, dimethyldecyl-, dimethylundecyl-, and di methyldodecyl (perfluoroheptyl amidopropyl] ammonium halides. Thus, a preferred compound is dimethyldecyl[3- (perfluoroheptyl) amidopropyl] ammonium bromide.

Several of the trialkyl[(perfluoroheptyl)amidopropyl] ammonium halides utilized according to the present invention are available commercially and therefore their preparation constitutes no part of the invention. According to one embodiment the trialkyl[(perfluoroheptyl) amidopropylJammonium halides may be obtained by reacting an appropriate perfiuoro acid with an N, N-dialkylamino propane to form the corresponding perfluoroamidopropyldialkyl amine and thereafter reacting this product with an alkyl halide. For example, in preparing dimethyldecyl [3- (perfluoroheptyl) amidopropyl] ammonium bromide, one can react perfluoroheptanoic acid with N-methyl-N-decyl diamino propane to form [Ii-(perfluoroheptyl) amidopropyl1methyldecyl amine which is then reacted with methyl bromide to form the quaternary ammonium salt.

The amount of polyhydric alcohol required in accordance with my invention will vary with the tendency of the oil itself to foam, with the particular polyhydric alcohol employed, and with the severity of the conditions to which the oil is subjected. In general, the amount should exceed the saturation solubility of the polyhydric alcohol in the oil at the highest temperature to which the oil will be heated in use. The combined weight of the polyhydn'c alcohol and the trialkyl[(perfluoroheptyl)amidopropyl] ammonium halide is usually between about 0.01 and about 2.0 percent of the weight of the oil, the preferred amount being ordinarily in the order of about 0.05 to about 1.0 percent. In some instances where the oil itself does not foam excessively to begin with, the anti-foam composition, i.e., the combined weight of the polyhydric alcohol and the trialkyl[(perfluoroheptyl)amidopropyl] ammonium halide may be about 0.001 percent. The quantity of the trialkyl[(perfluoroheptyl)amidopropyl] ammonium halide varies with the particular polyhydric alcohol employed. In general, the weight ratio of the trialkyl[ (perfluoroheptyl)amidopropyl1ammonium halide to polyhydric alcohol is between about 1 to 1 and 1 to 100. However, in some cases the weight ratio of the trialkyl[ (perfluoroheptyl amidopropyl ammonium halide to polyhydric alcohol may be 1 to 1000.

In preparing my improved oil compositions, the oilinsoluble liquid polyhydric alcohol and the trialkyl[(perfluoroheptyl)arnidopropyl]ammonium halide may be incorporated in the oil or oil composition by any suitable method capable of producing a stable, fine dispersion of the anti-foam composition in the oil. For example, where the oil to which the anti-foam composition is added has the viscosity of a heavy mineral oil, the anti-foam composition may first be incorporated in an oil lighter in viscosity than the oil to be improved, or other suitable carrier, and the resulting composition may then be introduced into the oil to which it is desired to embody antifoam properties simply by mixing and agitation. A line dispersion of the anti-foam composition is thus readily obtained. A convenient anti-foam concentrate for such use comprises 10 percent of anti-foam composition. To add 0.001 percent anti-foam composition to the final oil would require the addition of 0.01 percent of the antifoam concentrate. Where it is desired to form directly a dispersion of the anti-foam composition in the oil, various commercial colloid mills and gear pumps may be employed. The use of gear pumps is particularly advantageous in embodiments of this invention wherein fine dispersions of the anti-foam composition are produced in the oil during use. Other methods and apparatus may also be employed in depersing the anti-foam composition in oils or oil compositions.

It is sometimes advantageous to first disperse the antifoam composition in a part of the oil to be improved to form a concentrate thereof and then add this concentrate dispersion to the remainder of the oil. Such concentrate dispersions can be readily prepared as stable uniform compositions. For instance, a mixture of oil, polyhydric alcohol and trialkyl (perfluoroheptyl) amidopropyl] ammonium halide in the desired proportions may be continuously circulated through a gear pump until a stable concentrate containing a uniform dispersion of the antifoam composition in the oil is obtained. Thus, standardized concentrates can be prepared which can be added to the lubricating compositions as needed. In such case, the desired amount of concentrate is added to the oil composition, and the mixture is agitated until uniform.

Also, such concentrates are themselves valuable antifoam compositions. As they contain a preformed, dispersed, insoluble liquid phase, they quickly break oil foams as well as suppress foaming in general. For instance, when added to oil or oil compositions which have foamed, they readily destroy the foam present and stop further foaming. -In such cases, they can be quickly blended with oils, or oil compositions and uniformly incorporated therein before serious foaming occurs.

For such purposes, oil concentrates containing from about 0.1 to about 10 percent by weight and more of finely dispersed anti-foam composition are advantageous. By adding from about 0.01 to about 20 percent of such concentrates to a lubricating oil, improved lubricants having marked resistance to foaming are readily and easily obtained.

The anti-foam composition of the invention is effective in suppressing and preventing foaming in oils and oil compositions generally including mineral oils and fatty oils such as vegetable and animal oils and fatty oil compositions. The anti-foam composition of the invention is, however, particularly advantageous for use in mineral and synthetic lubricating oils. Examples of some of the synthetic lubricating oils which can be improved in accordance with present invention are organic esters including di-2-ethylhexyl sebacate, dioctyl phthalate and dioctyl azelate; polymerized olefins; co-polymers of alkylene glycols and alkylene oxides; polyorgano siloxanes which are known commercially as silicones and are made up of silicon and oxygen atoms wherein the silicon atoms may be substituted with alkyl, aryl, alkaryl, aralkyl and cycloalkyl radicals such as dimethyl silicone polymers, diethyl silicone polymers, ethyl phenyl silicone polymers and methyl phenyl silicone polymers; mixtures thereof; and the like.

The anti-foam composition of the invention and concentrates thereof are useful in any oil or oil composition whether used as a lubricant or not and in which it is desired to prevent foaming. They are particularly effective, however, in combating foaming in synthetic oils used as lubricants.

The lubricating oil of my invention can obtain other additive agents including detergents, such as the oilsoluble salts of metallic or organic bases with fatty acids, petroleum sulfonic acids, etc.; oiliness and extreme pressure agents, such as aromatic chlorine compounds, stabilized chlorinated parafiins, sulfurized fatty oils, and high molecular weight ketones and esters; viscosity index improvers, such as the high molecular weight polymers of isobutylene and the polymers of methacrylic esters; pour point depressants, such as a condensation product of chlorinated wax and naphthalene and a condensation product of chlorinated wax and phenol followed by further condensation of this reaction product with organic acids; antirust agents, such as cocoamine isoamyl octyi orthophosphate and cocoamine dioctyi orthophosphate;. and corrosion and oxidation inhibitors, such as 2,6-ditertiary butyl-4-methy1phenol, triphenyl phosphite, tributyl phosphite, beta naphthol, and phenyl betanaphthylamine. Some of these agents and especially the detergents tend to promote foaming. By the present invention, foaming caused by the addition of such foam inducing detergents can be effectively suppressed without deleteriously atfecting the beneficial characteristics given to the oil by the detergents.

The efiectiveness of my anti-foam composition comprising a polyhydric alcohol and a trialkyl[(perfiuoroheptyl)amidopropyHammonium halide may be demonstrated by means of ASTM test designation D892-46T in which the oil or oil composition is controliably aerated under fixed conditions so that the results obtained in a series of tests are directly comparable.

In the following specific examples there are illustrated by means of the above test the advantageous results obtained by incorporating in a mineral oil and in a synthetic lubricating oil a mixture of glycerol and dimethyldecyl[3- (perfluoroheptyl)amidopropyl] ammonium bromide. In these specific examples, the synthetic lubricating oil was a mixture composed of 66% parts by volume of methyl phenyl silicone and 33 /3 parts by volume of di-Z-ethylhexyl sebacate. The mineral oil was a highly refined 5 paraffinic oil having as typical properties a gravity of 27.2 API; a viscosity of 1156 SUS at 100 F.; a viscosity of 99 SUS at 210 F.; a viscosity index of 101; a flash point (O.C.) of 550 F.; a fire point (O.C.) of 625 F.; and a. pour point of 0 F.

In preparing samples of oil for the foam test, an antifoam composition was first prepared by admixing 5 parts by weight of the dimethyldecyl[3 (perfluoroheptyl)- amidopropyl] ammonium bromide with 95 parts by weight of glycerol. The anti-foam composition thus obtained was then dispersed in the lubricating oil by means of a Waring Blendor.

vention containing 0.25 percent by weight of a 5 weight percent dimethyldecyl [3-(perfluoroheptyl) amidopropyl] ammonium bromide in glycerol were substantially the same as those of the base oil as shown by the inspection data in the following table.

L35 l wy volume methyl phenyl silicone; by volume di-2-ethylhexyl se aca e.

l 5 weight percent dimethyldecyl [3-(perfluoroheptyl)-amidopropyl] ammonium bromide in glycerol.

While my invention has been described above with reference to various specific examples and embodiments, it will be understood that the invention is not limited to such illustrative examples and embodiments, and may be variously practiced within the scope of the claims hereinafter made.

I claim:

1. An oil composition of reduced foaming properties comprising a major amount of an oil having foaming tendencies, said oil being selected from the group consisting of mineral oils and synthetic lubricants having oillike properties selected from the group consisting of organic esters, polymerized olefins, copolymers of alkylene glycols and alkylene oxides and polyorgano silicone polymers and a small amount, sufficient to decrease said foaming tendencies, of an anti-foam composition consisting essentially of a substantially oil-insoluble liquid polyhydric alcohol selected from the class consisting of glycols and glycerol and a trialkyl[(perfluoroheptyl)amidopropyl]- ammonium halide wherein one of said alkyl radicals contains from 8 to 12 carbon atoms and each of the other two said alkyl radicals contains from 1 to 4 carbon atoms and wherein the weight ratio of said trialkyl[(perfiuoroheptyl)amidopropyl1ammonium halide to said polyhydric alcohol is between about 1 to 1 and l to 1000.

Composition, Percent By Weight A B 0 D E F G Lubricating Oil:

Synthetic 0% (Kiley vtilume pllilegyi e silicone an M 37 v0 ume y y 100 99.98 99.96

sebacate) fineraEOil-flfif' APL Ant 0am ompos ion:

6 wt. percent Dimethyldecyl[3-(perfluoroheptynamidopropyllammomum bromide in glycer l Foam Test (ASTM 13892-461):

Foaming Tendency, ml. at 5 min.-

at 75 F at 200 F at 75 F. after test at 200 F- The data summarized in the above table show that improvement in the foaming characteristics of a synthetic oil at 75 F. can be obtained with as little as 0.02 percent by weight of the anti-foam composition of the invention. The data show further that substantial improvement at 200 F. may require at least about 0.04 percent by weight of the anti-foam composition and that complete suppression of foam at 75 F. and 200 F. may require about 0.06 percent by weight. By comparing compositions F and G, it will be noted that complete supprcssion of foam in a mineral oil can also be obtained with 0.5 percent by weight of the anti-foam composition of the invention.

The properties of an improved composition of the in- 2. An oil composition of reduced foaming properties comprising a major amount of an oil having foaming tendencies, said oil being selected from the group consisting of mineral oils and synthetic lubricants having oillike properties selected from the group consisting of organic esters, polymerized olefins, copolymers of alkylene glycols and alkylene oxides and polyorgano silicone polymers and about 0.001 to about 2.0 percent by weight, sufiicient to decrease said foaming tendencies, of an antifoam composition consisting essentially of a substantially oil-insoluble liquid polyhydric alcohol selected from the class consisting of glycols and glycerol and a trialkyl- [(perfluoroheptyl)amidopropyl] ammonium halide wherein one of said alkyl radicals contains from 8 to 12 carbon atoms and each of the other two said alkyl radicals contains from 1 to 4 carbon atoms and wherein the weight ratio of said trialkyl[(perfluoroheptyl) amidopropyl]ammonium halide to said polyhydric alcohol is between about 1 to 1 and 1 to 1000.

3. An oil composition of reduced foaming properties comprising a major amount of an oil having foaming tendencies, said oil being selected from the group consisting of mineral oils and synthetic lubricants having oillike properties selected from the group consisting of organic esters, polymerized olefins, copolymers of alkylene glycols and alkylene oxides and polyorgano silicone polymers and about 0.01 to about 2.0 percent by weight, suflicieut to decrease said foaming tendencies, of an antifoam composition consisting essentially of a substantially oil-insoluble liquid polyhydric alcohol selected from the class consisting of glycols and glycerol and a trialkyl[ (Perfluoroheptyl)amidopropylIammonium halide wherein one of said alkyl radicals contains from 8 to 12 carbon atoms and each of the other two said alkyl radicals contains from 1 to 4 carbon atoms and wherein the weight ratio of said trialkyl (perfiuoroheptyl) amidopropyl] ammonium halide to said polyhydric alcohol is between about 1 to 1 and 1 to 1000.

4. An oil composition of reduced foaming properties comprising a major amount of an oil having foaming tendencies, said oil being selected from the group consisting of mineral oils and synthetic lubricants having oillike properties selected from the group consisting of organic esters, polymerized olefins, copolymers of alkylene glycols and alkylene oxides and polyorgano silicone polymers and about 0.01 to about 2.0 percent by weight, sufiicient to decrease said foaming tendencies, of an antifoam composition consisting essentially of about 1 to 100 parts by weight of glycerol and 1 part by weight of dimethyldecyl[3 (perfluoroheptyl)amidopropyl]ammonium bromide.

5. The oil composition of claim 4 wherein the synthetic lubricant is a mixture of methyl phenyl silicone and di- 2-ethylhexyl sebacate.

6. A composition adapted to impart foam resisting properties to a mineral oil when added thereto in an amount corresponding to about 0.01 to about 20 percent by weight comprising a concentrate dispersion of a mineral oil containing from about 0.1 to about 10 percent by weight of an antifoam composition consisting essentially of a substantially oil-insoluble liquid polyhydric alcohol selected from the class consisting of glycols and glycerol and a trialkyl (perfluoroheptyl) amidopropyl] ammonium halide wherein one of said alkyl radicals contains from 8 to 12 carbon atoms and each of the other two said alkyl radicals contains from 1 to 4 carbon atoms and wherein the weight ratio of said trialkyl[(perfluoroheptyl)amidopropyl] ammonium halide to said polyhydric alcohol is between about 1 to 1 and 1 to 1000.

7. A composition adapted to impart foam resisting properties to a synthetic lubricant having oil-like properties selected from the group consisting of organic esters, polymerized olefins, copolymers of alkylene glycols and alkylene oxides and polyorgano silicone polymers when added to said lubricant in an amount corresponding to about 0.01 to about 20 percent by weight comprising a concentrate dispersion of said synthetic lubricant containing from about 0.1 to about 10 percent by weight of an antifoam composition consisting essentially of a substantially oil-insoluble liquid polyhydric alcohol selected from the class consisting of glycols and glycerol and a trialkyl (perfluoroheptyl)amidopropyl] ammonium halide wherein one of said alkyl radicals contains from 8 to 12 carbon atoms and each of the other two said alkyl radicals contains from 1 to 4 carbon atoms and wherein the weight ratio of said :trialkyl[(periluoroheptyl)amidopropyHammonium halide to said polyhydric alcohol is between about 1 to l and l to 1000.

8. The oil composition of claim 7 wherein the synthetic lubricant is a mixture of methyl phenyl silicone and di-2- ethylhexyl sebacate.

9. An anti-foam composition consisting essentially of a substantially oil-insoluble liquid polyhydric alcohol selected from the class consisting of glycols and glycerol and a trialkyl (per-fluoroheptyl) amido-propyl] ammonium halide wherein one of said alkyl radicals contains from 8 to 12 carbon atoms and each of the other two saidalkyl radicals contains from -1 to 4 carbon atoms and wherein the weight ratio of said trialkyll(Perfluoroheptyl)amidopropyl] ammonium halide to said polyhydric alcohol is between about 1 to 1 and 1 to 1000.

10. An anti-foam composition consisting essentially of glycerol and dimethyldecyl [3-(pcrtluoroheptyl)amidopropylJ-ammonium bromide in a proportion of about 1 to parts by weight of glycerol per part by weight of dimethyldecyl [3-(perfluoroheptyl) amidopropyl] ammonium bromide.

References Cited in the file of this patent UNITED STATES PATENTS 2,394,596 Davis et a1. Feb. 12, 1946 2,603,599 Trautman July 15, 1952 2,764,602 Albrecht Sept. 25, 1956 2,764,603 Albrecht Sept. 25, 1956 FOREIGN PATENTS 736,351 Great Britain Sept. 7, 1955 

1. AN OIL COMPOSITION OF REDUCED FOAMING PROPERTIES COMPRISING A MAJOR AMOUNT OF AN OIL HAVING FOAMING TENDENCIES, SAID OIL BEING SELECTED FROM THE GROUP CONSISTING OF MINERAL OILS AND SYNTHETIC LUBRICANTS HAVING OILLIKE PROPERTIES SELECTED FROM THE GROUP CONSISTING OF ORGANIC ESTERS, POLYMERIZED OLEFINS, COPOLYMERS OF ALKYLENE GLYCOLS AND ALKYLENE OXIDES AND POLYORGANO SILICONE POLYMERS AND A SMALL AMOUNT, SUFFICIENT TO DECREASE SAID FOAMING TENDENCIES, OF AN ANTI-FOAM COMPOSITION CONSISTING ESSENTIALLY OF A SUBSTANTIALLY OIL-INSOLUBLE LIQUID POLYHYDRIC ALCOHOL SELECTED FROM THE CLASS CONSISTING OF GLYCOLS AND GLYCEROL AND A TRRIALKYL(PERFLUOROHEPTYL)AMIDOPROPYL)AMMONIUM HALIDE WHEREIN ONE OF SAID ALKYL RADICALS CONTAINS FROM 8 TO 12 CARBON ATOMS AND EACH OF THE OTHER TWO SAID ALKYL RADICALS CONTAINS FROM 1 TO 4 CARBON ATOMS AND WHEREIN THE WEIGHT RATIO OF SAID TRIALKYL$(PERFLUOROHEPTYL)AMIDOPROPYL)AMMONIUM HALIDE TO SAID POLYHYDRIC ALCOHOL IS BETWEEN ANOUT 1 TO 1 AND 1 TO
 1000. 